Plate Structures Research Articles

Low-frequency vibration and noise control in sandwiched composite locally resonant metamaterials-embedded plate structures

This study proposes a sandwiched composite locally resonant metamaterial (SLRM) system and SLRM-embedded plate structure (SLRMeP) to effectively control low-frequency vibrations and sound radiation. The wave control mechanism and configuration of the proposed system are more suitable and realistic to address practical low-frequency vibro-acoustic problems. A numerical model was proposed based on the material properties, unit dimensions, and mass ratios to determine the local resonance characteristics and bandgap formation. The experimental results on a full-scale SLRMeP measuring 3000 × 4200 × 210 mm confirmed the efficacy of the local resonance bandgap for controlling vibrations and sound radiation, achieving a 94.08% reduction in the acceleration response and a 15.13 dB reduction in the sound pressure level. Additionally, variations in mass ratio, achieved by altering the mass density or dimensions, yield distinct bandgap behaviors, offering strategies to enhance vibro-acoustic performance.

Ti-mesh bipolar plate design and optimization for enhanced PEM electrolyzer performance in water splitting

Proton exchange membrane (PEM) electrolyzers are promising devices for hydrogen production from water splitting, but their performance and stability are still limited by various factors. This paper studies the effects of different structures on the performance of PEM electrolyzers, focusing on the working temperature, water conductivity, and the structure of bipolar plate. The results show that higher temperature and lower water conductivity enhance the electrolyzer performance, by increasing the catalyst activity and the proton transport. Moreover, a novel structure using a platinum-coated titanium mesh-based bipolar plate is proposed and tested. This structure improves the performance of the electrolyzer, by optimizing the mass transport, pressure drop, and water management in the electrolyzer. A 23-cell electrolyzer with this structure is developed and demonstrated. The electrolyzer achieves a high performance and stability, with a cell voltage of 1.742 V, a voltage efficiency of 85.0%, and a hydrogen production rate of 1.14 Nm3/h at 0.99 A/cm2. The observed cell voltage for the PEM electrolyzer is consistent with the documented range, typically spanning from 1.55 to 1.90 V at a current density of 0.99 A/cm2. This suggests that our bipolar plate design simplifies PEM electrolyzer manufacture while maintaining comparable performance to existing electrolyzers.

New Accurate Flexural Analysis for Different Types of Plates in a Rectangular Sewage Tank by Utilizing a Unified Analytic Solution Procedure

In the present paper, a modified Fourier series approach is developed for new precise flexural analysis of three different types of concrete plates in a rectangular sewage tank. The bending problems of the bottom plate, side-plate, and the fluid-guiding plate are not easily solved via using the traditional analytic approaches. Based on the Fourier series theory, the present approach provides a unified semi-inverse solving procedure for the above plates by means of choosing three different kinds of Fourier series as the trial functions. Although all the trial functions are quite similar to the classical Navier-form solution, new, precise analytic flexural solutions for plates without Navier-type edge conditions (all edges simply-supported) are achieved, which is mainly attributed to employing the Stoke’s transform technique. For each case, the plate-bending problems are finally altered to deal with linear algebra equations. Furthermore, owing to the orthogonality and completeness of the Fourier series, the obtained solutions perfectly satisfy both the edge conditions and the governing partial differential equation of plates, which paves an easily implemented and rational way for engineers and researchers to provide new, exact designs of plate structures. The main contribution of this study lies in the provision of a unified solution procedure for addressing complex plate-bending problems across diverse boundary conditions. By employing a range of Fourier series types, this approach offers a comprehensive solution framework that accommodates the complexities inherent in plate analysis. The correctness of the present analytic solutions is verified against precise finite element method (FEM) results and ones available in the literature. Finally, the influences of foundation, edge conditions, and aspect ratio on flexural behaviors of plates are discussed in detail.

A Time Delay Estimation Interpretation of Extended State Observer-Based Controller With Application to Structural Vibration Suppression

This paper aims to investigate the disturbance estimation mechanism of extended state observer (ESO) from a new perspective: a time-delay estimation (TDE) interpretation. By drawing the concept of input-output linearization, ESO is transformed into an equivalent TDE form in frequency domain. The establishment of this relationship can lead to an improved understanding of ESO’s principle. In addition, ESO’s parameters for disturbance estimation are given with explicitly physical meanings. Furthermore, theoretical analysis from this perspective also results in a quantitative relationship between ESO estimation performance and its two tuning parameters including control gain <inline-formula xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink"> <tex-math notation="LaTeX">$b_0$</tex-math> </inline-formula> and bandwidth <inline-formula xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink"> <tex-math notation="LaTeX">$\omega _o$</tex-math> </inline-formula> . Theoretical results are evaluated by using an all-clamped plate structure with an inertial actuator, which is considered to be a typical benchmark for active vibration control. Extensive comparative experiments validate algorithm effectiveness. <italic xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">Note to Practitioners</i> —This paper was focused on the ability of extended state observer (ESO) to estimate total disturbances. The controlled system is a typical benchmark for active vibration control consisting of an all-clamped plate structure with an inertial actuator. The model uncertainties and external disturbances that bothers the system is compensated by the real-time estimation of the ESO. In order to facilitate practical engineering applications, the distinct physical meanings of ESO parameters are expounded with the help of the relationship between ESO and time delay estimation (TDE) established in frequency domain. Moreover, the influence of parameters control gain <inline-formula xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink"> <tex-math notation="LaTeX">$b_0$</tex-math> </inline-formula> and bandwidth <inline-formula xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink"> <tex-math notation="LaTeX">$\omega _o$</tex-math> </inline-formula> on ESO is qualitatively established. Therefore, the engineer can avoid fall into a trial-and-error strategy that could be laborious and time-consuming. Thus, this paper proposed a convenient way for practitioners interested in developing anti-disturbance control strategies based on ESO. The simplicity and the partial-model-based characteristics are also profitable in practice. Potential applications include robotic systems, smart structures and electrical drives. In the future, the improvements of ESO based on the proposed method to deal with the intractable disturbances should be taken in an effort.

Numerical study on the uniform distribution of flow field of airflow dryer

The uniformity of hot air flow inside the airflow dryer not only affects the moisture distribution at the outlet, but also affects the quality of the product. Based on the guide plate structure of the SH23A airflow tobacco dryer, a gradient curved guide plate dryer is designed, and the flow field distribution of the dryer is numerically investigated under different flow distribution conditions at the hot air inlet and flue gas inlet. The results show that the airflow uniformity is affected by the flow distribution at the inlet of the heated air and the inlet of the cigarette smoke, the structure of the guide plate, etc., the non-uniformity coefficient decreases with the increase of hot air inlet flow rate. The non-uniformity coefficient of tapered arc deflector decreases by 9–12 %.

Design and optimization of liquid-cooled plate structure for power battery of the pure electric excavator

With the increasing pressure of energy transformation and environmental protection, the trend of electrification of construction machinery is becoming more and more obvious. In this paper, based on a small pure electric excavator which is still in the stages of research and development, a liquid-cooled heat dissipation structure (liquid-cooled plate) is designed according to the power battery pack scheme. The overall shape of the liquid-cooled plate is designed as a symmetrical serpentine flow channel. Geometrically, the symmetrical serpentine flow channel is a combination of a straight flow channel and a runway-shaped flow channel. Then the conjugate heat transfer simulation model was established by using the CFD software Ansys Fluent. The results show that the initial scheme can not guarantee the temperature homogeneity of the battery pack. Therefore, the liquid-cooled heat dissipation scheme was optimized and compared. Firstly, a liquid-cooled plate was added on the original basis, and multiple sets of simulations were carried out with the length of the linear flow channel as a variable. The results show that appropriately increasing the length of the straight flow channel at the entrance of the liquid-cooled plate has a marked effect on improving the heat dissipation performance.

Experimental analysis of sugarcane and coconut shell fibre impregnated with glassfiber composite for aircraft application

Natural fibers' adaptability, sustainability, and environmental friendliness make them useful in a variety of sectors and applications. Sugarcane bagasse and coconut shell, which are made from industrial waste, have great promise as a sustainable substitute for traditional materials. How sugarcane bagasse, coconut shell, and glass fiber interact with an epoxy composite matrix is the subject of the present experimental investigation. The Semi Compression Moulding Machine (SCMM) was used to make the following compositions: 50 % matrix, 20 %-30 % sugarcane fiber, 10 %-25 % glass fiber, and 5 %-10 % coconut shell fiber. The ASTM-compliant composite plate structure that was built has a tensile strength ranging from 20 to 25 MPa and a tensile fatigue failure stress of 7 to 8 MPa, all tested over a range of 14,000 to 16,000 cycles. The scanning electron microscope (SEM) was used for morphology examination, while X-ray diffraction (XRD) was employed for crystalline properties. The use of natural fibers impregnated into glass fiber reinforced composites allowed for the creation of low density, very stable materials, which were essential for the skin and control surfaces of aircraft.

悬摆式同步覆土水稻直播机的设计与试验

In order to solve the problem of mechanical direct seeding of rice seeds on the exposed soil surface, which is affected by bird and mouse damage, rain and sun exposure, etc., a pendulum-type synchronous soil-covered rice direct seeding machine was developed. In order to clarify the leakage and anti-entanglement performance of the mulching plate, linear function type, quadratic function type and exponential function of the sliding blade mulching plate were designed, and the mulching plate structure, straw distribution spacing and suspension rotation speed were used as independent variables. Using straw entanglement rate and straw interference rate as evaluation indicators, a full-factor experimental study was carried out to determine the optimal structure of the mulching plate; a pendulum-type synchronous soil covering live broadcast EDEM simulation model was established, and field experiments were conducted to verify its synchronous soil covering performance. The test results show that the exponential function of the sliding blade mulching plate has the best performance, and the soil covering rate of the three soil covering plate structures is 87.37~98.54 under the conditions of forward speed 0.6~1.0 m/s and suspension rotation speed 90~150 r/min. %, the covering soil thickness is 5.08~5.84 mm. This research can provide reference for rice mechanical direct seeding technology and equipment.

Response spectrum-based analysis of airborne radar random vibration and multi-point control improvement

During the flight of a UAV (unmanned aerial vehicle), the LiDAR device undergoes random vibrations due to the changing flight attitude and wind speed conditions of the UAV. It is important to control the frequency and amplitude of the vibrations within a reasonable range by means of a damping structure. As the vibrations caused by various factors during flight are random and non-linear, this paper innovates the analysis principle and damping control means for the random vibrations of airborne optoelectronic devices. The response spectrum analysis theory is used to establish the shock response spectrum, and an optimised and improved recursive digital filtering method is used to fit the frequencies of random vibration to the synthetic shock response. Considering the uncertainty of the vibration excitation signal, a virtual excitation method is used for the first time to simulate the random vibration to which the radar may be subjected in the air, and to simplify the calculation steps. The shock plate structure is designed using a multi-point control method to innovate a passive response to the random excitation. Finally, a modal analysis of the synthesised impact response was carried out. It is verified that the first six modal frequencies are controlled within 220 Hz, realising the frequency reduction. The amplitude of the three x, y, and z directions is controlled to within 0.5 mm, thus achieving vibration damping.

Evaluation of Post Tension Runway Plate as Retrofitting Simulated with Compression In-Plane Force in Numerical Approach

The swelling of soil can result from fluctuations in its moisture content, causing it to expand and contract. To mitigate this, structures in direct contact with the soil may require retrofitting. Post-tensioning is one such method that can enhance the stiffness of the structure without altering its properties, thereby helping to prevent damage from expansive soil. This research presents a novel methodology for the design of retrofitting runway pavements using post-tension plates, employing a numerical approach that considers various influencing factors. The methodology integrates the use of differential and Kerr foundation equations, employing the Levy method to ascertain the deflection of the plate structure. Soil parameters are derived from soil sampling and laboratory tests, while loads are determined based on prior research findings and governmental regulations. The findings of the study indicate that the thickness of the plate structure influences its deflection, as greater thickness results in increased stiffness within the structure. Increasing the thickness of the plate enhances stiffness and diminishes deflection. Regarding the direction of post-tensioning, employing tension in both directions proves most effective, resulting in a reduction of deflection by 22.11%. However, this model demands higher costs compared to others due to the increased requirement for tendon post-tensioning. As an alternative, aligning the direction of post-tensioning with the direction of load movement can lead to a reduction of 15.14% in plate deflection, while incurring lower costs compared to applying post-tensioning in both directions.

Tomography of wall-thinning defect in plate structure based on guided wave signal acquisition by numerical simulations

Tomography of wall-thinning defect in plate structure based on guided wave signal acquisition by numerical simulations

A T-splines-oriented isogeometric topology optimization for plate and shell structures with arbitrary geometries using Bézier extraction

Recently, the non-uniform rational B-splines (NURBS) have been considerably employed in modeling plate and shell structures, or developing the related size, shape or topology optimization methods for their design. However, the NURBS with the tensor product feature strongly hinders the effectiveness of the optimization on complex structures. The primary intention of the current research is to propose a new T-splines-oriented Isogeometric Topology Optimization (T-ITO) method and then address the critical design problem of plate and shell structures with arbitrary shapes in practical applications. Firstly, the Bézier extraction is utilized in the T-splines to map the geometrical model into a family of Bézier elements, each of which is presented by a local Density Distribution Function (DDF) for elementary topology. A global DDF is constructed by an assembly of all local DDFs with a natural connection to the present structural topology. Secondly, the T-splines-based IsoGeometric Analysis (T-IGA) formulation with the Bézier extraction for complex plate and shell structures is developed using the Kirchhoff-Love theory, where a universal numerical implementation framework is constructed, including the Rhino, MATLAB, export modules with all geometric information and import modules for the analysis. Thirdly, a mathematical formulation for plate and shell structures with arbitrary geometries is developed using the T-ITO method to improve structural loading-capability, and the sensitivity analysis with respect to design variables is rigorously derived in detail. Finally, several numerical examples of plate and shell structures with both regular and elaborate geometries are tested to demonstrate the validity, effectiveness, superiorities and indispensability of the T-ITO method.

A THERMAL BEHAVIOUR STUDY OF NATURAL FIBER-REINFORCED POLYMER COMPOSITE/HONEYCOMB CORE SANDWICH PANELS

The unique honeycomb structure has provided good modulus with a lightweight material, especially in aerospace and vehicle applications. Realizing that the thermal analysis of natural fiber honeycomb sandwiches was still lacking in observation, the research needs to investigate thermal transfer characteristics to promote engineering demand. The objective of this research was to investigate honeycomb sandwiches' thermal behaviour by implementing local natural fibers of coconut, oil palm, and sugar cane for sheet plate structure through experimental and numerical analysis. The natural fiber was varied by weight content with the ratio of composite given in a range of 0%wt. - 8%wt. The results have demonstrated that the face sheet plate was paramount part to absorb thermal flow. The study displayed the low thermal conductivity of the face sheet will counter significantly the heat transfer of the honeycomb structure. The experimental investigation found that the coconut fiber successfully performs as an insulator in a honeycomb sandwich which reached 6.78 W.m-1K-1 of thermal conductivity which was an 85.86% improvement as an insulator. While palm oil and sugar cane presented at 11.12 W.m-1K-1 and 10.59 W.m-1K-1, it was slightly higher compared to the coconut. In the numerical investigation, fiber distribution development was successfully performed in a honeycomb sandwich sheet plate composite. The thermal conductivity showed a difference from the experimental, where the higher thermal resistance was shown by palm oil and sugar cane at 8.22 W.m-1K-1 and 8.16 W.m-1K-1, respectively.

Effects of three-dimensional type flow fields on mass transfer and performance of proton exchange membrane fuel cell

Developing state-of-the-art bipolar plate structures, to optimize fluid distribution, is essential to achieve better cell performance. In this paper, a three-dimensional model of PEMFC is developed and two cathode-side flow field structures are designed: two-dimensional and three-dimensional types. The two-dimensional type is the traditional “bipolar plate + gas diffusion layer” flow field structure, easily resulting in uneven distribution of reactant gas and other problems. This study describes three novel three-dimensional type flow fields (metal foam, fine-mesh, and wire-mesh). Through comprehensive performance analysis using numerical simulations, it is found that the three-dimensional type flow fields significantly improve mass transfer and output performance compared to two-dimensional type flow fields. The proposed three-dimensional type flow fields create forced convective fluid flow. It further enhances the diffusion dispersion of reactant gas, thus making fuller use of the active region. Among them, the wire-mesh flow field shows the best performance in terms of oxygen distribution, water distribution and electrical properties. The net output power density produced is 0.75068 W cm−2, higher than parallel flow field by 32.78%.

Research on the Simulation Method for Equivalent Stiffness of Bolted Connection Thin Plate Structures

Bolted connections are widely used in assembly structures, and their dynamic characteristics are often affected by stiffness, damping, excitation, and other factors. In order to solve the problems of low computational efficiency of fine modeling and large computational error of linearized equivalent modeling of bolted structures, this paper proposes a dynamic characteristic parameter identification method for bolted structures based on the multiscale method and considering the influence of nonlinear factors. In this method, the bolted connection characteristics are simulated in the form of a combination of shear stiffness, torsional stiffness, nonlinear stiffness, and viscous damping coefficient and identified according to the test measurement frequency and frequency response function. At the same time, by establishing the nonlinear dynamic model of bolted structure, the influence of different bolt preloads and excitation forces on the dynamic characteristics of bolted structure is studied.

Numerical simulation and experimental study of fluid–structure interactions in elastic structures based on the SPH method

The study of fluid–structure interactions in elastic structures is highly important in hydraulic structural engineering. This paper adopts the smooth particle hydrodynamics (SPH) coupling method to simulate dam failure water impact elastic plate flow and solid coupling problems. In addition, a numerical simulation is performed on the study of the free surface flow impact of the elastic plate structure on the main dynamic characteristics, including the impact force distribution and the change process. Additionally, the elastic structure of the vibration amplitude and frequency change rule, as well as the drastic changes in free surface flow, are also carried out. In this paper, the synchronous finite element algorithm is used to analyze the problem to obtain FEM results Additionally, two-dimensional benchmark physical tests are designed for dam-break water flow impacting an elastic plate are conducted, focusing on a comparative analysis of the numerical results of the SPH method with the results of physical tests and verifying the validity, accuracy, and superiority of the SPH coupling method for solving the problem of fluid‒solid coupling in elastic structures. On this basis, to explore the relevant physical quantities that cannot be measured or described during the test process, the flow–solid coupling characteristics of the elastic plate impacted by water flow are further understood by analyzing the nature of the flow field, the change in the flow–solid force of the elastic plate and the change rule of the frequency spectrum. The results show the following: (i) The jumps in velocity between the streams and the strong curvature of the free liquid surface lead to the creation of vortices at the cavities. (ii) The flow solid force under the impact of water flow increases and then decreases, and the smaller the deformation of the elastic structure is, the greater the force is. (iii) The vibration frequency of the fixed end of the elastic structure gradually decreases along the free end frequency, and the larger the deformation of the free end of the elastic plate is, the weaker its vibration response is. In addition, the natural frequency of the elastic plate under water flow impact is slightly lower than that under free vibration of the elastic plate. The related research results provide reference and guidance for the fluid–structure interaction problem.

Design of patch-shaped lens with thickness variations for elastic wave focusing in thin-plate structures

In mechanical engineering, focusing on elastic waves is pivotal for applications, such as energy harvesting, shock mitigation, and wave manipulation. While phononic crystals have historically been a key method for managing wave propagation, this study explores a novel technique. This method introduces gradient refractive-index (GRIN) lenses by altering the plate thickness and creating localized high-refractive-index zones. Unlike traditional methods, this localized GRIN approach aims to overcome the fabrication and structural limitations, particularly in thin structures. The patch-shaped lenses offer the potential for elastic wave focusing in thinner structures without any degradation of structural performance. Through numerical analysis, we established design principles and examined the elastic wave propagation and focusing characteristics across various thickness variation profiles. This study conducts a thorough analytical and experimental evaluation of these lenses to confirm their effectiveness, structural robustness, and suitability for optimizing wave concentration in various mechanical engineering applications. The research represents an alternative, innovative, and promising pathway in the field of wave focusing, transcending the traditional constraints of thin plate structures.

Natural frequencies and modal shapes of folded sandwich plates made of porous core and FG-CNTRC coating layers resting on two parameters elastic foundation

Folded structures hold significant importance in aerospace technology due to their distinct design, effectively reconciling strength with a lightweight framework. Within aerospace applications, these structures fulfill diverse roles, serving as pivotal elements in aircraft wings, fuselage sections, and essential components of spacecraft and satellites. This study delves into the free vibration behavior of folded sandwich plates composed of a porous core and functionally graded carbon nanotube-reinforced composite (FG-CNTRC) coatings, resting on a two-parameter elastic foundation. Leveraging first-order shear deformation plate theory (FSDT), elasto-dynamic equations are established for each individual plate segment. Utilizing the two-dimensional generalized differential quadrature method (2D-GDQM), these equations are discretized. Subsequently, by applying boundary conditions to all six edges, including traditional clamped, simply supported, and free configurations, and incorporating continuity conditions for displacements, forces, and moments at the joint borders, natural frequencies and modal shapes are extracted for the folded plate structure. The validity of the proposed formulation and results is demonstrated by comparing them with numerical examples for both composite flat and folded plates. This comparison provides strong support for the accuracy and reliability of the present study. The study comprehensively examines the influence of various parameters on natural frequencies, including modal shape visualizations under different boundary configurations, plate thickness, crank angle, porosity parameter, core thickness, foundation stiffness, and CNTs distribution type.

Low-frequency vibration attenuation of metamaterial sandwich plate with lever-type inertial amplified resonators

The utilization of sandwich plate structures is widespread across diverse engineering fields owing to their advantageous high stiffness-to-weight ratio properties. However, these lightweight and thin-walled structures commonly encounter challenges related to inadequate vibration performance in the low-frequency range, imposing significant limitations on their applications. This paper thereby presents a design for a metamaterial sandwich plate that incorporates lever-type inertial amplified resonators (IA-MSP) to achieve a low-frequency bandgap and effective vibration attenuation capability. The bandgap characteristics and vibration behavior of the IA-MSP are comprehensively studied through an integrated approach involving theoretical analysis, numerical simulations, and experimental studies. The dynamic model of the IA-MSP is mathematically formulated, theoretically elucidating the underlying inertial amplification mechanism within the proposed metamaterial sandwich plates. The investigation on vibration transmission is conducted to analyze the vibration attenuation performance of the IA-MSP, utilizing both numerical simulations and experimental methods. The findings reveal that lever-type resonators amplify the mass motion, thereby enhancing the effective mass of the system and leading to a reduction in the frequency associated with the coupled mode of the bandgap. This amplification facilitates the attainment of a low-frequency bandgap without the need for utilizing the inclusion of additional centralized mass or heavy local resonators. By altering the lever ratio R of the lever-type inertial amplified resonators, precise fine-tuning and optimization of the low-frequency bandgaps are achievable. Compared with traditional metamaterial sandwich plates with local resonators (LR-MSP) featuring identical geometrical and material characteristics, the proposed IA-MSP characterized by an R-value of 2 exhibits boundary frequencies that are half of those observed in the LR-MSP. With an increase in the lever ratio R of the IA-MSP, a noticeable trend emerges a decrease in the lower boundary frequency, accompanied by a corresponding shift of the bandgap towards lower frequencies. The present study's outcomes are anticipated to hold significant promise in the realm of sandwich plate design, with a specific focus on furnishing vibration attenuation capabilities at lower frequencies.

Evaluation of Different Fixation Methods Combinations After L-Shaped Osteotomy Reduction Malarplasty: An In Vitro Biomechanical Study.

This in vitro study compared the stability of different fixation method combinations for the zygomatic complex after simulated L-shaped osteotomy reduction malarplasty, a common facial contouring surgery in East Asia with high postoperative complications due to poor fixation methods. The study used 108 zygoma replicas with various fixation methods combinations in the zygomatic body (L-shaped plate with short wing on zygoma and on the maxilla, two bicortical screws, one bicortical screw with L-shaped plate, square plate, and rectangular plate) and zygomatic arch (Mortise-Tenon structure, 3-hole plate, and Mortise-Tenon structure plus short screw). The failure force under incremental load was applied through the Instron tensile machine to a well-stabilized model using a rubber band simulating the masseter muscle and recorded the increasing force digitally. ANOVA test was used for comparison between recorded values (P < 0.05). The results showed that the most stable combination was a six-hole rectangular plate and a Mortise-Tenon structure plus one short screw (358.55 ± 51.64 N/mm2). The results also indicated that the placement vector of the fixation methods around the L-shaped osteotomy and the use of the two-bridge fixation method were important factors in enhancing the stability of the zygomatic complex. The study suggested that surgeons should choose appropriate fixation methods based on these factors to reduce postoperative complications and improve surgical outcomes. This journal requires that authors assign a level of evidence to each submission to which Evidence-Based Medicine rankings are applicable. This excludes Review Articles, Book Reviews, and manuscripts that concern Basic Science, Animal Studies, Cadaver Studies, and Experimental Studies. For a full description of these Evidence-Based Medicine ratings, please refer to the Table of Contents or the online Instructions to Authors www.springer.com/00266 .